1. Field of the Invention
The present invention relates to a handpiece for use in small-scale surgery and microsurgery, for example, oral surgery or surgery in the ear, nose and throat area. The handpiece includes a handpiece sleeve and a collet chuck which is rotatable about an axis and is arranged in the handpiece sleeve. The collet chuck is spring-biased and can be released by an actuating member. The collet chuck serves to hold a tool and is composed of two tubular members which are movable relative to each other along the axis of rotation of the collet chuck.
2. Description of the Related Art
Although handpieces of the above-described type are similar to dental handpieces, they cannot be compared to dental handpieces because the requirements made of surgical handpieces are substantially greater in all respects.
Thus, in the case of surgical devices, the cooling medium used is not water or a water spray, but a physiological saline solution, which increases the requirements made with respect to the corrosion resistance of all materials used in the device.
When such surgical devices are used, the operation is carried out substantially deeper below the skin or the tooth base than when dental handpieces are used, so that the danger of germs being introduced into the wound is significantly greater and particularly more dangerous, which means that the instruments are sterilized much more frequently than dental handpieces. Because the surgical handpieces are frequently heated during sterilization, the surgical handpieces are subjected to substantially greater thermal stress than dental handpieces. In addition, during sterilization there is the danger that salt is crystallized out of the saline solution which evaporates in the heat, so that there is the danger of clogging of ducts.
Finally, compared to procedures carried out by dental devices, surgical procedures usually are accompanied by severe bleeding, so that it has been found impossible in practice to reliably and permanently prevent blood from entering the instrument. Moreover, since blood enters together with saline solution, the corrosion capacity of the saline solution is increased by being mixed with the blood.
Also, because of the inaccessibility of the work areas and the depth of the operation, the external diameters of the instruments should be as small as possible for reasons of accessibility and the size of the wounds to be produced, wherein, on the other hand, the drilling or cutting efficiency is higher in the bone than in the tooth.
Therefore, it has been for a long time the wish of the users of surgical instruments to have available a surgical handpiece which can be disassembled easily, quickly and without the use of tools, in order to make it possible that the handpiece can be cleaned or sterilized frequently and thoroughly. The assembly after cleaning should be as simple as the disassembly. The instrument should have external dimensions which are comparable to those of conventional surgical handpieces or dental handpieces.
Available in this area for example, is an instrument of the above-described type as disclosed in Austrian Patent 393 788. In that instrument, a collet chuck is used for holding the tool, wherein the collet chuck is held in a closed position by the force of a spring.
For opening the collet chuck, the handpiece sleeve is rotated, which causes pressure rollers to be rotated together with the handpiece sleeve, wherein the pressure rollers roll off along a rolling plane of a pressure sleeve which facilitates a longitudinal movement of the pressure sleeve and, thus, a release of the collet chuck.
The construction of this known instrument has various disadvantages. Thus, it is necessary that the handpiece sleeve is constructed so as to be rotatable relative to the actual handpiece; the pressure rollers must be supported in such a way that the user of the handpiece does not have to apply significant forces when the collet chuck is to be tightened or clamped again; and the pressure rollers require a significant amount of space in radial direction. In order to be able to disassemble the handpiece, it is necessary to provide a special connection between the handpiece sleeve and another adjacently arranged sleeve which is called an actuating sleeve. Moreover, the positions of the two sleeves relative to each other and the position of operation of the collet chuck cannot be easily recognized.